1. Field of the Invention
The present invention relates to a composition for inducing brown adipocytes and inducing differentiation into beige adipocytes from white adipocytes, the composition including butein, a butein derivative or a pharmaceutically available salt thereof as an active ingredient, and a method of inducing the differentiation.
2. Discussion of Related Art
Obesity is triggered by hypertrophy of subcutaneous adipose tissues caused by accumulation of excessive energy as fats in a body when imbalance in a metabolic process occurs due to endocrinal, genetic and social environmental factors. The hypertrophy of the adipose tissues is a phenomenon in which sizes or numbers of adipocytes increase (hypertrophy or hypergenesis of the adipocytes), and may have an influence on retention of a local vein-lymph system, thereby causing a vascular tissue disease in dermis-subcutaneous tissues. Therefore, the obesity is recognized as an independent disease by definition, and World Health Organization deals with the obesity as a world-wide nutritional problem and recognizes it as a disease to be treated, not only a simple dangerous factor that ruins a health.
Neutral fats excessively accumulated in obese patients are stored in a liver or muscles, as well as adipose tissues, and thus induce insulin resistance. Accordingly, consumption of the excessively-stored neutral fats may result in preventing and treating obesity and metabolic diseases caused thereby. The adipocytes are largely classified into white adipocytes, brown adipocytes and beige adipocytes. The white adipocytes are stored in a large fat globule of the neutral fat, usually found in an abdominal cavity in large numbers, and known to have a negative influence on health. It is reported that the brown adipocytes contain a larger number of mitochondria and smaller fat globules than the white adipocytes, and may be induced by maintenance of a body temperature through heat generation and a proper exercise. Mice induced to contain a large number of brown adipocytes relatively induce a decrease in body weight and an increase in calorie burning with respect to obesity caused by high fat diet (HFD), and thus show an effect on obesity and metabolic diseases. In addition, it is known that uncoupling protein-1 (UCP-1) is expressed on a high level from the brown adipocytes, and plays a critical role in generating heat in the form of calorie burning, not calorie storage, in adipocytes. In addition to the brown adipocytes, beige adipocytes are also recognized as important adipocytes. The beige adipocytes are induced from white adipocytes that are harmful to health by an exercise or stimulation such as a cold, and have lower phenotypes of the white adipocytes, but have characteristics of the brown adipocytes, leading to an increase in expression of UCP-1. It is known that the beige adipocytes are also helpful for obesity and metabolic diseases, similar to the brown adipocytes found in mice. In addition, most of the helpful brown adipocytes found in humans are known as beige adipocytes, and thus concerns on conversion of or induction of differentiation of the white adipocytes harmful to health into the beige adipocytes relatively helpful for health are increasing.
Therefore, regulation of activity of UCP-1 and genesis of beige (or brown) adipocytes are becoming main subjects for studies, and the studies on this have been being executed (Korean Patent Publication No. 10-2012-0049214), but these are still inadequate.